Diperisophthalic acid compositions

ABSTRACT

DIPERISOPHTHALIC ACID IS FORMULATED WITH INERT HYDRATED SALTS WHICH RETAIN WATER OF HYDRATION AT TEMPERATURES UP TO 30*C. BUT GIVE UP CONSIDERABLE WATER OF HYDRATION BELOW THE NORMAL DECOMPOSITION TEMPERATURE OF THE ACID SUCH AS BELOW 130*C. TO DAMPEN THE DETONABILITY OF THE DIPERISOPHTHALIC ACID.

United States Patent 3,770,816 DIPERISOPHTHALIC ACID COMPOSITIONS Donald R. Nielsen, Corpus Christi, Tex., assignor to PPG Industries, Inc., Pittsburgh, Pa.

No Drawing. Continuation-impart of application Ser. No. 418,541, Dec. 15, 1964. This application July 23, 1969, Ser. No. 844,164

Int. Cl. C07c 73/10 US. Cl. 260-502 R 8 Claims ABSTRACT OF THE DISCLOSURE Diperisophthalic acid is formulated with inert hydrated salts which retain water of hydration at temperatures up to 30 C. but give up considerable water of hydration below the normal decomposition temperature of the acid such as below 130 C. to dampen the detonability of the diperisophthalic acid.

RELATED APPLICATIONS This application is a continuationin-part of copending application Ser. No. 418,541, filed Dec. 15, 1964.

THE INVENTION Diperisophthalic acid is capable of liberating active oxygen for bleaching and various oxidizing reactions. A characteristic of this peracid is its tendency to be explosive or detonable when exposed to elevated temperatures or shock. It also has a tendency to decompose in a nonexplosive manner and hence lose its active oxygen content.

According to copending application Ser. No. 308,323, filed Sept. 12, 1963, the stability of perphthalic acids, notably diperisophthalic acid, is improved by incorporating with the peracid an alkali metal or alkaline earth metal salt of an acid having an ionization constant at 25 C. for the first hydrogen of at least 1X10- preferably not less than 1X10"? Among those salts specifically mentioned are sodium sulfate, magnesium sulfate, and like alkali metal or alkaline earth metal sulfates such as potassium sulfate, ammonium sulfate, and lithium sulfate. Sodium bisulfate or potassium bisulfate as well as other alkali metal bisulfates are also mentioned.

This invention concerns perisophthalic acids, notably diperisophthalic acid. More particlarly, it concerns solid particulate non-detonable compositions of diperisophthalic acid.

In accordance with the present invention, it has been discovered that the detonability or explosibility of diperisophthalic acid can be materially dampened, even obviated, by incorporating with the peracid a hydrated salt which retains at atmospheric pressure water of hydration (or crystallization) at temperatures of at least 30 C. but gives up considerable water of hydration at a temperature above 30 C., notably from about 60 C. to 130 0, possibly 150 C., more preferably in the temperature range of 85 C. to 130 C.

While considerable latitude is permissible in the amount of inert, inorganic hydrated salt which is used, the amounts of such salts usually are substantial. Generally, sufficient salt is used to provide compositions containing 0.25 or more parts (but rarely more than about or 10 parts lest the composition be too highly diluted) water of hydration (which is released in the desired temperature range, e.g., such as between 60 C. and 130 C.) per part by weight of diperisophthalic acid. As hereinafter discussed, according to certain embodiments, as little as about 0.1 part of such water of hydration per part of diperisophthalic acid may be used to advantage in providing protection against peracid detonation.

Recommended are compositions of diperisophthalic acid in combination with inorganic hydrated salts which give up or release substantial water of hydration (crystallization) at temperatures above about C. but below about C. While the hydrated salts which release all their water of hydration between 60 C. and C. (or more medially between 85 C. and 130 C.) may offer advantage, effective compositions are attained when the hydrated salts release a portion of their water of hydration within this temperature range. Thus, salts which have a stable hydrated form above 150 C. may be used if they release water of hydration between 60 C. to 150 C., that is, such salts with several hydrates are contemplated.

Especially preferred particulate free flowing compositions are those of diperisophthalic acid and hydrated salts which have their hydrated forms stable at temperatures below 60 C. but which give up their water of hydration at temperatures above 60 C. but below the temperature at which the diperisophthalic acid detonates, i.e., about 120-130 C. Those hydrated salts which under normal conditions (including conditions which the compositions are apt to encounter during storage and shipment) release any significant amount of water of hydration have disadvantages. For example, release as liquid Water of hydration can interfere with the compositions free flowing characteristics and possibly cause decomposition of the peracid. Ergo, if the composition is destined during storage and shipment for exposure to cooler climatic conditions it can include hydrated salts which retain all their water of hydration at temperatures below 30 C., but release water of hydration (some or all) somewhat above 30 C. (and below 60 C.). When the formulation is to encounter the warmer climatic conditions, the hydrated salt should be one which retains water of hydration at the warmer temperature, e.g., usually a salt which retains water of hydration below about 60 C.

It is better if the water of hydration content of the salt is high enough so that admixture of reasonable quantities thereof will provide compositions having an adequate diperisophthalic acid content. In this regard, compositions normally will contain at least about 0.5 percent and more preferably at least 1.0 percent by weight of the diperisophthalic acid basis the acid and hydrated salt. Compositions with active oxygen contents of between 0.05 and 5 or possibly up to 10 percent by weight (basis the acid and hydrated salt) are to be preferred over those whose peracid content is more diluted.

A further desirable characteristic of the hydrated salt is that it be slightly acidic or essentially neutral, i.e., it should not be strongly alkaline. Thus, preference is for those hydrated salts whose 1 weight percent solutions in distilled water have a pH of from. about 3 to about 8.

Any of a wide number of one or more inert hydrated salts meeting these aforementioned qualifications combine with diperisophthalic acid to provide non-detonable compositions. Among the hydrated salts which may be specifically noted are magnesium sulfate'7H O (commonly called epsom salt), magnesium formate dihydrate, magnesium benzoate trihydrate, magnesium acetate tetrahydrate, magnesium nitrate (Mg(NO -6H O), calcium sulfate (CaSO -2I-I O), calcium lactate hydrate, calcium sodium sulfate (CaSO -2Na SO -2H O), the recognized hydrates of the various alkali metal aluminum sulfates including sodium aluminum sulfate, potassium aluminum sulfate, ammonium aluminum sulfate and aluminium sulfate (notably the octadecahydrate). Other suitable hydrates include lithium formate monohydrate, sodium sulfate decahydrate, sodium acetate trihydrate and the substantially neutral or acidic hydrates of alkali metal polyphosphates such as Na H P O -SH O. Salts of sodium, potassium, aluminum, calcium and magnesium are of particular appeal.

Depending upon the ultimate manner in which the diperisophthalic acid is to be formulated and used, compositions of the hydrated salt and acid may also include a variety of other constituents. Salts such as are described in my copending application Ser. No. 308,323, filed Sept. 12, 1963, which impart stability to the perisophthalic acid and discourage or deter decomposition or loss of active composition includes a salt such as ammonium sulfate, the amount of solid water (water of hydration) required to protect against undue decomposition can be reduced considerably. Use of such salts is particularly apropos to avoid undue dilution of the diperisophthalic acid with 5 oxygen upon standing may also be included along with hydrated salt or to permit use'of hydrated salts which the peracid and hydrated salt. otherwise would not have a high enough water of hydra- It would not normally be considered desirable to intion content. Usually from about 0.05 to 2.0 parts or more corporate easily oxidized organic materials which can of such a decomposable salt by weight of the diperisocontaminate the composition or promote instability of phthalic acid functions well. Other ammonium salts as diperisophthalic acid. However undesirable as this may the term is herein used which are useful for this function be, efiective marketing of the diperisophthalic acid, may include primary, secondary or tertiary amine salts such dictate it be combined with synthetic organic detergents as sulfates, chlorides, phosphates, nitrates or acetates, such as alkyl sulfates, sulfonates and the like. Similar quaternary ammonium salts, ammonium polyphosphates dilemmas are encountered if the diperisophthalic acid and polyborates. is compounded with other materials which are strongly It is especially important when the composition is to alkaline such as these detergents. be either coated or encapsulated at elevated temperatures This difliculty y ha alleviated, however, y Coating to recognize the advisability of employing a hydrated encapsulating either the stmhgly alkaline ingredients salt which does not give up water of hydration at temor the mixture of diperisophthalic acid and hydrated salt peratures b low 60 C. or even 80 C, Many of the coat- With a Suitable inert Protective coaiillg 0f Pafafhn WaX, ings are efficiently applied at temperatures somewhat P y y alcohol, P y y P y y methacrylate, above 60 C. For example, paraffin wax may be applied a gelatin, carboxymethyl cellulose, or various by a method which includes the step of first melting. stantially inert inorganic materials including calcium Melting temperatures in excess of ambient temperatures sulfate, sodium sulfate and the like, to segregate the deter- (i e,, a high a about 60 C. or somewhat higher) but begeht, alkalihe agent of like material from the dipefisolow the decomposition temperatures of the diperisophthalic phthalic'hydl'atad Salt mixture- Protected y Such acid thus can be involved. If the hydrated salt is one eapsulation or coating, the mixture y be cempeunded which loses water of hydration at temperatures which are or formulated with dry detergents or other materials. employed i th coating, the free flowing powdery char- It is also possible to alleviate this aforementioned difa teri tio of the composition may be lost and coated ficulty by techniques other than coating or encapsulation. inefficient.

F r p the particle size of Components f h The following examples illustrate the dampening effect mixtures y be adjusted to minimize y lack of 6 admixtures of hydrated salts have on diperisophthalic acid. patibility. Thus, mixtures of relatively coarse diperiso- EXAMPLE I phthalic acid granules are mixed with granulated detergent. These coarse diperisophthalic acid granules prefp p e pb hahc acid (analyzlng 95 to 97 percent by erably are formed by granulating a homogeneou mixweight diperisophthalic acid) was thoroughly mixed with ture of very finely divided diperisophthalic acid and finely the Salt and In the PIOPOIUOHS hsted h Tahle The divided hydrated salt, which granules are then mixed with sulting composition was then placed in a test tube in the granulated detergent. Alternatively, mixtures of an air bath provided by a stainless steel beaker heated pellets or large pellets in which the detergent components by a hot plate. The beaker was covered with a Teflon and the diperisophthalic acid-hydrated salt mixture are sheet and the air circulated while its temperature was physically separated maybe employed. raised at the rate of 5 C. to 7 C. per minute. Tempera- According to a further embodiment, the contemplated tures of the bath and sample were recorded continuously compositions of diperisophthalic acid and hydrated salt during the tests. Heating of the air bath continued until may have advantageously incorporated therewith amboth the air temperature and the sample temperature monium salts such as ammonium sulfate or ammonium were well above the normal decomposition temperature acetate which decompose or hydrolyze in the presence of C.-l30 C.) of the diperisophthalic acid.

TABLE I Air bath temp. at Maximum Additive DPI Dec0mtime of temp. after weight, weight, position deeomposldecomposi- Additlve grams grams temp., 0 tion, 0. tion, C.

AlNa(S04)z-12H2O 0.4 0.2 137-138 140 103-170 A1Na(SO4)2'12H20. 4.0 1.0 110 134 149 A1K(SO4)2-1ZHO-..--' 0.4 0.2 139 154 200 AlK(s0i)i-12Hso 4.0 1.0 153 193 1.6 0.4 115 158 189 4.0 1.0 113 100 13s MgSO4-7H2O 0. 2 0. 1 143 172 MgSO4'7H20- 4. 0 1. 0 98 154 10s MgsO4'7H2O s. 0 2. 0 120 15s 17s Mg(NO3)Z-6H20 o. 2 0. 1 110 122 157 Mg(N Om-GHzO 0.8 0. 4 120 175 A1(NO3)2'9H2O 0. 4 0. 2 110 115 170 A1(N0r)r-9H2O 0. 8 0. 4 105 125 139 onset-21120--- 0.4 0.2 131 130 1 DPI= Dlperisophthalic acid.

moisture at temperatures below the explosion temperature of the diperisophthalic acid into fragments which accelerate the peracid decomposition below detonation or explosion temperatures. In this fashion, energy from the diperisophthalic acid decomposition is expended at temperatures below those at which explosion will occur, thus reducing the energy available when the explosion temperature is reached during accidental overheating,

In all the tests reported in Table I, no explosion was observed, only some smoke. This indicates the compositions are protected against heat-induced detonation. Without additive present, even small amounts (0.1 gram) of the diperisophthalic acid when heated will detonate as evidenced by a loud pop.

Example II illustrates an exemplary free-flowing granular composition coated with about 0.5 weight percent such as by fire, friction or mechanical shock. When the 75 polyvinyl alcohol.

EXAMPLE II Additive: Weight percent Diperisophthalic acid 23 Isophthalic acid 0.5 Water 27.5 Aluminum sulfate 49 The aluminum sulfate and water are present as hydrated aluminum sulfate salt.

The composition of Example II was tested at ambient salt with the acid while it is water wet and thereby producing a free flowing composition. In the method of Silbert et al., hydrogen peroxide and isophthalic acid are reacted'in the presence of methanesulfonic acid to produce a slurry of diperisophthalic acid, methanesulfonic acid, hydrogen peroxide and water (generated by the reaction and decomposition of hydrogen peroxide). Upon filtration of the slurry and washing of the filter cake with deionized water, a water wet filter cake is obtained which is primarily diperisophthalic acid containing, by way of temperature Wlth blasting cap found 10 illustration, from 0.5 to 2 pounds of water per pound of de tol 1ab1e' In the f b astmg g E water insoluble organic component (mainly diperisowlthm t Sample P gi test e 3 u g phthalic acid). Direct drying of this filter cake to obplaced m a lead plpe' e astng cap 18 gxp o an tain dry diperisophthalic acid is not without peril. At temi effeci the o w f 15 peratures much in excess of 80' C., decomposition of d1luted diperisophthal ic ac1d results in consr era e e orthe peracid can be considerable Furthermore the dry manon of p product can be caused to explode by friction or by ex- Other tests mcludmg one which includes playing the d1- Osure to mechanical hock t flame of a Bunsen burner upon the complete formup s f 1 1 I t In preferred practices, dry, free fiowmg, powdery comlauon Indicate the formu anon of Examp e I ls no 20 positions of diperisophthalic acid are attained by adding flammable to the water wet filter cake (diperacid and water) a hy- As Example lildlcateshthe pomeglplated dratable salt (which contains less than its normal wauons {nay .Contam lsophthalic .acld an m1- g i i ter of hydration at the prevailing condition) in such prophthailc i (usually as i fi g i ig g i portion that the salt takes up the water in the filter cake the dlperacld) as as gl i t a to form a hydrate. If desired, heat produced by hydrai be understqod t Y may not a Ways B tion of the salt may be removed during or after the sible or convement to distinguish exactly how much of mixing h such lsophthahc ac1d i K F F E i Conversion of the wet diperisophthalic acid filter cake actlye oxygeil composltlonfi 180p i (mplu fi to a dry free flowing pulverulent material in this fashperisophthalic ig component 18 g 'g i ion thus circumvents the need for reliance upon elevated pensophthahc Is cleiaflyprqsent ent 6 active temperatures for efiecting drying (and the attendant degen content of lsolihthahc aclds 1S equttalem to more an composition of diperisophthalic acid) and forms most Perceni Welghf offlle p i conveniently a mixture of hydrated salts and the diper- Compositions of diperisophthalic ac1d and inert, 1norisophthalic acid ganic water-soluble hydrated aluminum salts, especially aluminum sulfate, exemplified by aluminum sulfate octa- These comp (PSI/[1on5 dlpensopilthahc 9 i hydecahydrate, are especially noteworthy and desirable. grated salts (wlth 3 out other Inert addltlyes i Among other things, aluminum sulfate hydrate is uniquely mg whlch lmpajrt enhanced ,protectfon effective in protecting diperisophthalic acid against detodecomposltlon) are F In those Servlces Whlch requ'lre nation Example 111 illustrates this 40 the generation of active oxygen. Thus, they are effective bleaching agents for textiles. They are used effectively 1n EXAMPLE HI commercial or domestic washing machines as bleaching Using the test procedure described in Example 1, these ag ually being employed in Conjunction With the results were obtained: commonly employed detergent. The composition is read- TABLE II fiil fidifiiiff by Peroxy Active Peroxy compound Additive compound oxygen Water Test results 24 3.9 26 No explosion. 24 3.9 30 0. 3g g3 Violpp; explosion. 24 1:6 25 No explosion. Do- AMSOi): 24 1.6 30 Mild explosion.

The sodium sulfate containing compositions were preily soluble at levels typically useful for such bleaching pared by mixing 0.6 gram of the dried peroxy compound purposes (particularly with water soluble inert salts). with 1.08 grams of Na S0 -10H O and 0.72 gram of an- Upon addition to the laundry solution, the composition hydrous sodium sulfate. A mixture of 1.25 grams of liberates its oxygen in a form which effectively promotes Al (S0 -18H 0 plus 0.64 gram of partially dried alubleaching. minum sulfate (20 percent water) with 0.60 gram of the Among the various conventional detergents with which peroxy compound provided the aluminum sulfate comthese compositions can be used are the alkali metal silipositions. cates, synthetic organic detergents including sodium do- The foregoing also illustrates that the hydrated salt decyl benzene sulfate or like alkali metal, alkyl or aralkyl content of the compositions is not necessarily present as sulfate or sulfonate, ethoxylated alkyl phenol adducts, a specific known hydrate but may be present as a mixture ethoxylated fatty alcohols, and the like. The composition of known hydrates with or without unhydrated salt. may be premixed with the detergent, particularly when Diperisophthalic acid herein contemplated may be progranulated or coated or encapsulated in a protective coatduced according to the method described in the article ing such as hereinbefore described or it may be sepaby Silbert, Siegel and Swern in the Journal of Organic rately added to the wash solution. When the composition Chemistry, vol. 27, pp .1336-1342 and US. Letters Patof diperisophthalic acid ils to be premixed with the deterent 3,143,562, granted Aug. 4, 1964. It has been found gent, it is advantageousy in a granulated form which according to an embodiment of this invention that dry has a density approximating that. of the detergent with pulverulent compositions of the diperisophthalic acid and which it is to be mixed. This assists in maintaining the hydrated inert salt herein contemplated are efficiently composition uniformly dispersed in the detergent. Usuprovided by admixing unhydrated or partially hydrated ally, the bleaching composition constitutes but a minor portion of the composition which results from its admixture with the organic detergent, typically representing less than 40 percent by weight of the total composition and quite frequently representing less than percent (often as low as 0.5 percent) by weight thereof.

Although the present invention has been described with, reference to specific details of certain embodiments, it is not intended that such details shall be regarded as limitations upon the scope of the invention herein described except insofar as details are included in the accompanying claims.

What is claimed is:

1. A solid free flowing composition comprising a mixture of diperisophthalic acid and hydrated magnesium sulfate having a water of hydration content of 0.25 to 5.0 parts per part by weight of diperisophthalic acid, while said diperisophthalic acid is in an undetonated condition, and containing at least 0.5 percent diperisophthalic acid by weight of the diperisophthalic acid and hydrated magnesium sulfate.

2. A solid free flowing composition comprising a mixture of diperisophthalic acid and hydrated magnesium sulfate, the amount of hydrated magnesium sulfate providing the composition with a water of hydration content of at least 0.1 part per part by weight of the diperisophthalic acid, while such diperisophthalic acid is in an undetonated condition, said composition containing at least 0.5 percent diperisophthalic acid by weight of the acid and hydrated magnesium sulfate.

3. A solid free flowing composition comprising diperisophthalic acid and hydrated aluminum sulfate which contains from 0.25 to 5 parts water of hydration per part by weight of diperisophthalic acid, while said diperisophthalic acid is in an undetonated condition, and between 0.05 and 5 percent by weight active oxygen.

4. A solid composition comprising a mixture of diperisophthalic acid and a water soluble inorganic hydrated salt, which salt at atmospheric pressure retains its water of hydration below 30 C. but releases said water of hydration below the normal decomposition temperature of diperisophthalic acid, wherein the hydrated salt is selected from the group consisting of aluminum sulfate, sodium aluminum sulfate, sodium potassium sulfate, sodium sulfate, ammonium aluminum sulfate, potassium aluminum sulfate, magnesium sulfate and calcium sulfate, said mixture containing at least 0.1 part of so releasable water of hydration per part by weight of diperisophthalic acid, while said diperisophthalic acid is in an undetonated condition.

5. A solid free flowing particulate composition comprising a mixture of diperisophthalic acid and sufficient hydrated sodium sulfate to provide at least 0.1 part water of hydration per part by weight of diperisophthalic acid, while said diperisophthalic acid is in an undetonated condition, whereby to dampen the detonability of the acid, said composition containing at least 0.5 percent diperisophthalic acid by weight of the acid and hydrated sodium sulfate.

6. A solid particulate free flowing composition comprising a mixture of diperisophthalic acid and hydrated inorganic salt selected from the group consisting of hydrated salts of sodium, potassium, calcium, aluminum, and magnesium wherein the anion of said salt is selected from the group consisting of sulfate, nitrate, and phosphate which salt at atmospheric pressure retains its water of hydration at temperatures up to 30 C. but releases water of hydration below C., said mixture containing at least 0.1 part of so releasable water of hydration per part by weight of diperisophthalic acid, while said diperisophthalic acid is in an undetonated condition and at least 0.5 percent diperisophthalic acid by weight of the composition.

7. The composition of claim 6 wherein the hydrated salt is selected from the group consisting of aluminum sulfate, sodium aluminum sulfate, sodium potassium sulfate, sodium sulfate, potassium aluminum sulfate, magnesium sulfate and calcium sulfate.

8. A solid composition comprising a mixture of diperisophthalic acid and hydrated inorganic salt selected from the group consisting of hydrated salts of sodium, potassium, calcium, aluminum and magnesium wherein the anion of said salt is selected from the group consisting of sulfate, nitrate and phosphate which salt at atmospheric pressure retains its water of hydration at temperatures up to 30 C. but releases water of hydration below 130 C., said mixture containing at least 0.1 part of so releasable water of hydration per part by weight of diperisophthalic acid while said diperisophthalic acid is in an undetonated condition.

References Cited UNITED STATES PATENTS 3,494,786 2/ 1970 Neilsen 260502 3,494,787 2/1970 Lund et al 117100 FOREIGN PATENTS 560,389 9/1957 Belgium 260502 R OTHER REFERENCES Remy: Treatise on Inorganic Chemistry, vol. 1, pp. 71-76 (1956).

BERNARD HELFIN, Primary Examiner W. B. LONE, Assistant Examiner US. Cl. X.R. 2521'86 

